A GIS-Centric Approach for Optimal Sensor Placement in Large-Scale Water Distribution Systems

Water quality monitoring is one of the most important tools to reduce potential exposure of contaminants and ensure provision of safe drinking water supply. Because of their extended service areas and numerous entry points, water distribution systems are inherently susceptible to external contamination. Sensors installed at key locations in the distribution system could provide vital warning against contaminant intrusion events. While various methods based on optimization theory have been proposed for locating monitoring sites, none have gained widespread acceptance or have actually been applied by the utility industry to real water distribution systems. Other methods based on coupling GIS and network modeling with statistical analysis have recently emerged as a powerful and practical tool for contaminant detection monitoring. This paper presents an extension of the geospatial hierarchical selection approach implemented in the USEPA PipelineNET model for solving the monitoring site location problem for a wide range of practical monitoring objectives. These objectives are derived from the network characteristics, hydraulic and water quality modeling results, site accessibility, proximity to critical infrastructure and population density defined by various GIS layers. The proposed approach can explicitly consider any combination of modeling scenarios, steady and unsteady flow conditions, multiple GIS layers, sensor placement costs, as well as a minimal distance between the sensors. In addition, it employs a robust and fast converging solution scheme for the selection of optimal monitoring sites for large scale networks. With this respect, the proposed method is advantageous to previous models. It is demonstrated by application to an example water distribution system and the results are shown to compare favorably with PipelineNET. The method can be effectively used to assist water utilities and consulting engineers in formulating and evaluating reliable water supply protection and management strategies and protecting public health.